Pneumatic action of mechanical players for musical instruments



Oct. 27, 1925. 1,558,723

H. THOMSON PNEUIATIC ACTION OF MECHANICAL PLAYERS FOR MUSICALINSTRUMENTS Filed Jan. 4, 1922 INVE/HWR', .36 HE Ramsay Patented Oct.27, 1925.

HENRY THOMSON, OF WAVERLEY, NEAR PATENT OFFICE.

SYDNEY, NEW SOUTH WALES, AUSTRALIA.

PNEUMATIC ACTION OF MECHANICAL PLAYERS FOR MUSICAL INSTRUMENTS.

Application filed January To all whom it may concern Be it known that I,HENRY THOMSON, a subject of the King of Great Britain, residing at Echo,33 Evans Street, W'averley, near Sydney, in the State of New SouthWales, Commonwealth of Australia, have invented new and usefulImprovements in Pneumatic Actions of Mechanical Players for MusicalInstruments, of which the following is a specification.

This invention relates to improvements in pneumatic actions ofmechanical players for pianofortes and other musical instruments, and inparticular to a new and improved construction of valve casing and valveintegers, and arrangement of the same relatively to the vacuum chest andan operating pneumatic, whereby functional and constructional advantagesin player actions, now unobtainable with existing constructions, will behad.

It is an object of the invention to provide a simple and compact valvestructure characterized by having air-tight seats for the valve-head,and constructed in such manner that the distance between said seats ineach of the seriesof actions is identical.

A 'furtherobject of the invention is to provide a valve structurewherein the top plate (now detachably fitted above the valve-head) isintegral with the valve casing, and wherein the requirement of having acap detachably fitted with screws or like fastenings beneath the valvediaphragm is dispensed with.

A still further object of the invention is to provide a compact valvestructure having a valve-head chamber and a diaphragm chamber integrallyformed with the valve casing and means whereby the former is in directcommunication with the operating pneumatic through the top platethereof. and the latter is in direct communication with the vacuumchest. By these means I. dispense with conduits or passages hithertoproposed, and eliminate friction and cushioning of air in said conduits,whereby the functional advantage of better repetitive work and lighterpedalling action is obtained in a specially simple and positive manner.

lVith these and other objects in View the invention consists of thefeatures of con- 4, 1922. Serial No. 526,894.

struction, combination and arrangement hereinafter fully described,reference being had to the accompanying drawings, where- 1n:

Figure 1 is a view in side elevation illustrating the valve casingconstructed integrally with the top plate of an operating pneumatic, andrigidly secured to the vac uum chest.

Figure 2 is a vertical section of the upper portion of Figure 1.

Figure 3 is a sectional plan on line l-1 of Figure 1.

Figure 4 is a view in vertical section illustrating the means of directcommunica tion between the diaphragm chamber and the vacuum chest.

Figure 5 is a plan of the valve-casing and integral top plate of thepneumatic.

Figure 6 is an underside plan of Figure 5 illustrating the portproviding direct communication of the valve-head chamber with thepneumatic, through the top plate of the latter.

Figure 7 is a front elevation of the valve casing, and illustrates thepositions of the tracker tube conduit, and a rigid disc of the diaphragminteger of the valve.

Figure 8 is a rear elevation of the valve casing, and illustrates theoutlet port from the diaphragm chamber.

Figure 9 is aside elevation of the valve casing, and illustrates therigid disc of the diaphragm with attached tracker tube conduit.

Figure 10 illustrates the construction of the rigid diaphragm disc.

Figure 11 is a vertical section illustrating a modification in theconstruction of the valve casing.

In these views 11 designates the casing of a vacuum chest 12 adapted forfixture within the pianoforte casing in approved manner and location. 13indicates the operating pneumatic and let the top plate thereof.

Each of the series of pneumatics is preferably of that constructionhaving two parallel floating plates 15 and 16 and a flexible envelope17, said floating plates being adapted to be drawn towards thestationary plate upon the collapse of the pneumatic following exhaust ofair therefrom.

These pneumatics are preferably arranged in a single longitudinal row,as is described in the specification of co-pending application forLetters Patent Serial Number 424,811 filed 18th November, 1920. Theconstruction and the arrangement of the operating pneumatics do not formany part of the present invention, and it will be understood that theimproved valve structure may be employed with pneumatics of other typethan that illustrated, such as pneumatics of conventional characterhaving a stationary top plate and a lower plate hingedly connectedthereto at one end.

, Constructed integrally with the pneumatic top plate 14 by metaldie-casting operations is a valve casing 18 having a bracket 19 tofacilitate its attachment to the vacuum chest casing by means of afastening screw 20, and a vertical partitioning wall 21 providing avalve-head chamber 22 and a diaphragm chamber 23 disposed on oppositesides of said wall, wherein is formed a cen tral inter-communicatingport 24.

The valve-head chamber has a port 25 in its outer wall for theintermittent admission of atmospheric air as hereinafter explained, andon its underside it has a port 26 formed through said top plate 14 inorder to be in direct communication with the in terior of thecollapsible pneumatic 13, thereby obviating the necessity of providing aspecial conduit or passage for the purpose. Small holes are provided inthe opposite walls of the chamber 22 to receive a pin or dowel 27 toretain the valve-head 28 in constant operative position within itschamber. The inner faces of the walls of the chamber 22 surrounding theports 24 and 25 form alternative seatings for said valve-head, and

as the valve casing is produced by diecast-,

ing operations, the distance between these seatings is identicalthroughout the series of actions, thereby ensuring uniformity of valveaction.

The diaphragm chamber 23 consists of a circular recess having a locatingshoulder 29 for a flexible diaphragm 30 of leather or like flexiblematerial, and constructed with a groove 31 to take over the tubularnipple 32 for connection to a tracker tube 33.

Formed in the rear wall of the diaphragm chamber is an elongated slot 34enlarged at 35 and functioning as a port arranged for directcommunication between said chamber and the vacuum chest 12. Thisconstruction dispenses with the hitherto proposed inclined passageconnected at one end to the valvecasingand at its other end to thevacuum chest, and eliminates friction and cushioning of air such aswould be prejudicial to rapid repetition work and tending to re ativelyheavy pedal action.

The ports 25 and 26 of the valve-head chamber, the port 24 in thepartitioning wall 21. and the elongated slot 34 in the wall of thediaphragm chamber are all produced in the operation of die-casting thevalve casing 18. Consequently economy of manufacture and accuracy ofproduction are obtained.

The valve-head 28 consists of a plurality of thin leather discs affixedtogether by rubber solution or other adhesive, and its travel is limitedby the distance apart of the seatings in its chamber 22.

I provide a diaphragm supporting disc 36 which is of a diameter tohaving adriving fit with the chamber 23. This disc is preferablyconstructed of ebony, but it may be made of wood, suitable compositematerial or as a metal stamping, and it has a concave inner face formingan air space 37 behind the diaphragm 30.

Said disc 36 is formed with a port 39 leading into the air space 37 fromthe tracker tube connecting nipple 32, and it has a bleed hole 40 whichregisters with the enlarged portion 35 of the slot 34 when the valveintegers are assembled.

Consequently said bleed hole communicates directly with the vacuumchest, and it enables the tracker tube 33 to be pneumatically exhausted.A slight suction is thus produced in the tracker tube suflicient toexhause the air therefrom when a duct in the tracker bar is covered bythe music sheet and prevent the operation of the valve, but insufficientto exhaust it when said duct is open. This suction retains the musicsheet in close contact with the tracker bar in the operation of theplayer mechanism, as will be readily understood.

A disc 41 of fabric gauze is provided at the rear of the diaphragm 30for the purpose of filtering the air admitted to said air space 37through the tracker tube. This filter disc and the flexible diaphragmare aifixed in position to the supporting disc 36 by adhesive applied totheir edges.

The valve stem 42 is afiixed at one end to the inner face of thevalve-head 28, and at its opposite end to a disc 43 of stout paperfastened to the diaphragm 30.- The valvestem may, however, be formedintegrally with the disc 43 which latter may be formed of papier-mach orother suitable material having the properties of lightness anddurability.

In assembling the integers of the improved valve structure, thevalve-head 28 is inserted in the chamber 22 when the retaining dowel 27is driven into the holes provided therefor in the valve casing. Adhesivefor the outer end of the valve-stem 42 is placed centrally on the innerside of said valve-head. The rigid disc 36 fitted with the tubularnipple 32, filtering screen 41, flexible diaphragm 30, and valve-stem 42is then placed intothe circular recess forming the diaphragm chamber 23,the groove 31 receiving said nipple and thereby functioning as a guidefor correct location.

The disc 36 is then driven inwardly until the edge of the diaphragm 30abuts against the locating shoulder 29. A coating of shellac is thenapplied around said diaphragm supporting disc, thereby ensuring that -aperfectly air-tight joint is effected between the same and the diaphragmchamber 23 of the valve casing, and dispensing with the requirement ofproviding a cap or cover element with ordinary attachment screws or thelike.

According to the modification illustrated in Figure 11, the port 26leading directly from the valve-head chamber 22 to the operatingpneumatic13 through its top plate 14 is made slightly less in lengththan the diameter of the valve-head 28. Formed in the end wall of saidchamber 22 is a slot 43 of such length and width as will permit thevalve-head being readily inserted into its chamber for assembly of thevalve integers, when an air-tight cover 44 of leather or other suitablematerial is firmly secured over said slot as by the use of an adhesive.The provision of this slot 43 allows inspection or removal andreplacement of the valve-head to be effected merely by removing thecover 44, thereby avoiding the necessity of removing the fabric 17 ofthe pneumatic 13 for such purpose.

hen the musical instrument is not in use, the valve-head 28 is seatedagainst the partitioning wall 21 closing communication between thevalve-head chamber 22 and the vacuum chest 12. Atmospheric air passesinto said chamber 22, thence directly to the pneumatic 13 permitting thelatter to be maintained inflated.

In action and when the perforated sheet, travelling across thetracker-bar closes a duct in the latter, a vacuum is formed in the space37 behind the flexible diaphragm 30 permitting it to rest in a neutralor inoperative position which condition is aided by the exhaust of airthrough the bleed hole 40. The valve-head 28 then rests upon its innerseat in the partitioning wall 21.

\Vhen the tracker-bar duct is opened by a perforation in the travellingmusic sheet coinciding therewith, atmospheric air is admitted to thespace 37 behind the diaphragm 30 in greater quantity than can beexhausted through the small bleed hole 40. The diaphragm 30 is of largerarea than the valvehead 28, as is illustrated, and advantage is therebytaken of the larger area of diaphragm material which is exposed tovacuum, and notwithstanding the weakening caused by the exhaust throughthe bleed hole 40, a force is exerted on said diaphragm 30 overbalancingthe atmospheric pressure exerted on the valve-head 28, causing thelatter to be thrown rapidly across from its inner seat against the wall21 to its outer seat around the port 25, thereby closing communicationbetween the atmosphere and the pneumatic 13. The pneumatic is thendirectly connected to the vacuum chest 12 by way of port 26 in the topplate 14, the port 24 in the partitioning wall 21 and the elongated slot34 in the wall of the diaphragm chamber 23, causing the exhaust of thepneumatic and by its collapsing action the actuation of the pianoforteaction to strike a note.

WVhen the duct in the tracker-bar is subsequently closed by thetravelling music sheet, the Valve-head 28, having a constant tendency tobe seated against the partitioning wall 21 by atmospheric pressure, actsthrough the valve-stem 42 on the ballooned diaphragm 30, similarly as ifimpelled by a weak spring, thereby forcing the entrapped air in thespace 37 outwardly through the bleed hole 40 into the vacuum chest 12until the valve-head is permitted to resume its inner seat, opening theport 25 to atmosphere when the diaphragm 30 is brought to its neutral orinoperative position.

Although the valve casing in its preferred embodiment is constructed bymetal die casting operations, it will be understood that a valvestructure according to my invention and within the scope of the appendedclaims can be made of wood or other approved material and produced byany means found suitable in manufacturing operations.

What I do claim is 1. In pneumatic actions of players for musicalinstruments, an operating pneumatic having a plate constituting a fixedwall thereof arranged with an integral laterally extending casingarranged with a valve chamber therein in communication with thepneumatic through an opening in the plate, a diaphragm chamber arrangedin said casing, alined openings in opposite walls of the casing one ofsaid openings communicating with the diaphragm and valve chambers of thecasing and the other in open communication with the valve chamber andatmosphere, and a valve in the valve chamber connected with the diazphragm through the opening connecting the diaphragm and valve chambersto control said openings and operative to connect the pneumatic with thediaphragm chamber and to shut the pneumatic ofl? from the atmosphere orto connect the pneumatic with the atmosphere and shut it off from thediaphragm chamber for the purpose specified.

2. Operating neumatics for pneumatic players for musical instruments asclaimed in claim 1 in which the casing having the diaphragm and valvechambers is arranged with a slot. in the lateral wall of the casing forinsertion and removal of the valve, and a removable air tight closurefor said slot.

3. In pneumatic actions of mechanical players for musical instruments, avacuum chamber, an operating pneumatic including a plate with a casingconstructed integral therewith having a partition to arrange said casingwith a valve chamberand a diaphragm carrying chamber at opposite sidesof said partition, said partition. having a port to connect saidchambers, a port in the wall of the valve chamber in opposed relation tothe port in the partitionopening to the atmosphere, a port in the platein communication with the valve chamber and pneumatic, a valve in thevalve chamber connected to the diaphragm through the port connectingsaid chambers operative from the diaphragm to control the opening andclosing of the ports in the partition and the port opening to theatmosphere, and a port in the wall of the diaphragm chamber incommunication with the vacuum chamber.

4. In pneumatic actions of mechanical players for musical instruments, avacuum chest, an operating pneumatic including a rigid plate having acasing integral therewith and arranged as a bracket to mount thepneumatic upon the vacuum chest, said casing having a partition toarrange the same with a valve carrying chamber and a diaphragm chamberand having a port therein to connect said chambers, a port in the wallof the valve chamber in opposed'relation to the port in the partitionopening to the atmosphere, a port in the. plate, to connect the valvechamberand pneumatic, a port in the wall of the diaphragm chamber at oneside of the diaphragm and communicating with a port in the vacuum chest,a port in the wall of the diaphragm chamber at the opposite side of thediaphragm arranged for connection to a tracker tube, and a valve in thevalve chamber connected to the diaphragm through the port connectingsaid chambers and operative from the diaphragm to control the openingand closing of the port in the casing partition and the port in thevalve chamber'opening to the atmosphere;

5. In pneumatic actions for mechanical players of musical instruments, avalve casing constructed with a recess forming a dia phragm chamber, arigid disc, a flexible diaphragm secured to said disc and an air spacebetween sa1d disc and sa1d diaphragm, sa1d disc tightly fitting sa1drecess to form a closure to said diaphragm chamber.

6. In pneumatic actions for mechanical players of musical instruments, avalve casing constructed with a recess forming a diaphragm chamber, arigid disc concaved 011 its inner side, a flexible diaphragm secured tosaid disc, an air space at the rear of said diaphragm, a bleed hole insaid disc, and a tracker tube, tubular connection fitted to said discand communicating with said air space, said disc being adapted to form aclosure to said diaphragm chamber.

7. In pneumatic actions for mechanical players of musical instruments, avalve casing constructed with a chamber accommodating a valve-head andwith a diaphragm chamber, an inter-communicating port between saidchambers, a slot in a wall of said diaphragm chamber, a rigid dischaving a concave inner face and tightly fitting said diaphragm chamber,adiaphragm secured to said disc and having an air space at its rear, atubular nipple for connection to a tracker tube fitted to said disc andcommunicating with said air space, a bleed hole in said disc registeringwith said slot, a valvestem afiixed at one end to said diaphragm and atits opposite end to said valve-head.

8. In pneumatic actions for players for musical instruments, a pneumaticincluding a plate having an integral casing with a partition separatingthe casing into a valve chamber and a recess at the opposite side ofsaid partition, a closure for the recess carrying a diaphragm at theinner side with a space between the closure and diaphragm, a port insaid partition to connect the valve chamber and recess at one side ofthe diaphragm, a port in the wall of the valve casing in opposedrelation to the partition port opening to the atmosphere, a' port in theplate to connect the pneumatic and valve chamber, a port in the wall ofthe recess at one side of the diaphragm for connection to vacuumcreating means, a bleeder opening in the closure in communicationwith-the recess port and with the space between the diaphragm and recessclosure, a second port in the recess closure in communication with thespace between the closure and diaphragm arranged for connection of atracker tube, a valve in the valve chamber to control the opening andclosing of the opposed ports in the wall of the valve chamber andpartition, and a stem to operatively connect the valve with thediaphragm through the portof the partition.

In testimony whereof I aflix my signature.

HENRY THOMSON.

